FY2019 Narrative In FY2019, we explored new directions in further identifying subpopulations that experience high levels of tobacco use disparities. For example, using the Health Information National Trend Surveys (HINTS), we examined how prevalence of cigarette smoking varies jointly by race/ethnicity and marital status. While previous studies often pooled married individuals with those who cohabiting with a partner in a single category, we decided to keep these two groups separated. And to our surprise, cohabiting individuals were more likely to smoke cigarettes than those who were married, and the difference was more profound among non-Hispanic blacks then in non-Hispanic whites. In a different project, used data from the Tobacco Use Supplement to the Current Population Surveys (TUS-CPS), we examined heterogeneity in tobacco use behaviors in the US black population by global region of origin. We found that US-born and Europe-born blacks living in the US had similar prevalence of cigarette smoking and menthol cigarette smoking, but Africa-born and West-Indies-born blacks living in the US has much lower prevalence of cigarette smoking and menthol cigarette smoking. These findings suggest that targeted interventions on US-born blacks are more likely to reduce tobacco use disparities. We continued to examine factors that explain tobacco use disparities in the US population. For example, we assessed the prevalence of adopting American College Health Association recommended tobacco-free policies among a sample of US postsecondary educational institutions. We found that only 20% of the sampled institutions adopted recommended policies. Further, compared to public institutions, proprietary institutions were much less likely to adopt these policies. Since racial/ethnic minority students are more likely to enroll in proprietary institutions, our findings revealed that these students are potentially less likely to be protected from the harm of tobacco. We also examined trends in environmental tobacco exposure among US children. After analyzing the National Health and Nutrition Examination Survey (NHANES) 1999-2014, we found that prevalence of environmental tobacco exposure has declined over time. However, in 2013-2014, non-Hispanic black children (vs. non-Hispanic white children), children living under or near poverty (vs. children living above poverty), and children living in rental homes (vs. own homes) were more likely to be exposed to environmental tobacco, highlighting the lack of progress in reducing environmental tobacco exposure disparities. Tobacco marketing, including product features, advertising, and promotions, continues to be influential on tobacco use disparities. In terms of product features, using data from the Population Assessment on Tobacco and Health (PATH) Study, we found that non-Hispanic blacks were more likely than non-Hispanic whites to believe that flavored e-cigarettes were easier to use than non-flavored e-cigarettes. We also found that such perception was associated with susceptible to e-cigarettes, subsequent e-cigarette initiation and current use. These findings highlight the potential of flavored e-cigarettes in differentially influencing e-cigarette use among non-Hispanic blacks. In terms of advertising, in a different PATH Study project examining youth engagement of online tobacco marketing, we found that Hispanic and non-Hispanic black (vs. non-Hispanic white), and sexual minority male (vs. straight male) were more likely to engage with online tobacco marketing. In terms of promotions, especially regarding direct-to-consumer marketing, we found that, according to the PATH Study data, those who self-identified as sexual minorities (vs. heterosexual) and those with recent difficulties paying important bills (vs. no difficulties) were more likely to report receiving tobacco discount coupons through direct mail and e-mails, as well as to redeem these coupons for tobacco products. We also found that these coupons are potentially affecting tobacco use behaviors among US youth. In a longitudinal analysis of the PATH Study youth sample, we found that youth who were repeatedly exposed to these coupons were more likely than those who were not exposed to these coupons to report past 30-day use of cigarettes, e-cigarettes, cigars, smokeless tobacco, and hookah. With the emergence of new pod-based e-cigarette products (e.g., JUUL), we conducted studies (in collaboration with extramural investigators) to examine its penetration in the US populations. In the first study, we found that among a US sample of youth adults, 6.8% reported past 30-day use of JUUL, and word-of-mouth from friends/family was the most common source of information about JUUL. In a second study with a national sample of adult smokers, we found that 9.8% of adult smokers reported past 30-day use of JUUL, while the most common source of information about JUUL was internet advertising. In a third study, we found that 12.9%, 4.4%, and 2.1% of US youth reported past 30-day use of JUUL, Suorin, and Vuse, respectively. The prevalence was higher among US young adults (18.1%, 6.7%, and 6.2%, respectively). In a fourth study, we examined the how JUUL Labs research sponsorship may influence the scientific integrity of their research and published our conclusion in the Lancet. Collaborating with the FDA/NIH PATH Study team, we examined several factors related to tobacco use in various populations. For example, we assessed youth access to tobacco products, and found that the most common sources of tobacco products was through their social network. However, 10.5%-23.2% of past 30-day youth tobacco users reported purchasing tobacco products themselves, highlighting the compliance with youth tobacco access law still have room to improve. When examining harm perceptions of various tobacco products among youth and adults, we found that these perceptions varied somewhat by product, race/ethnicity, and other social determinants. We also found that these perceptions demonstrated a bi-directional relationship with tobacco use among youth. In another PATH Study analysis, we examined how cigar package quantity influences cigar smoking behaviors, a behavior that is more prevalent among non-Hispanic blacks. We found that smaller package quantities were associated with initiation of cigar smoking, highlighting how regulating package quantities may reduce cigar use in the population. A new line of our research examined the health impact of tobacco. For example, using the Florida Youth Tobacco Survey, we found that secondhand exposure to e-cigarette aerosols was positively associated with asthma exacerbation among youth with asthma. In another analysis using the National Health Interview Surveys and the linkage to the National Death Index, we found that dual and poly-tobacco users have comparably, and sometimes higher mortality rates than exclusive cigarette smokers. These new findings on health effects of tobacco use allow us to better understand how tobacco use disparities impact health disparities in the US.